Aiming to the problems that Mean-Shift algorithm costs low computation, but easy to fall into local maximum, and
huge computation of Particle Filter tracking algorithm leads to low real-time processing capacity, according to the need
of real stereo vision measurement system, a kind of tracking algorithm which combines Mean-Shift and Particle Filter by
essentiality function is proposed. Under the condition without occlusion, Mean-Shift is used to track object. When object
is occluded, Particle Filter is applied to accomplish the later object tracking. These two algorithms alternate by a defined
threshold. The tracking algorithm is used into real stereo vision measurement system. Experiment result indicates that the
algorithm takes on high efficiency, so it is of high practicability.